A near-contact binary: CN Andromedae


ASTRONOMISCHE NACHRICHTEN, vol.326, no.2, pp.127-133, 2005 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 326 Issue: 2
  • Publication Date: 2005
  • Doi Number: 10.1002/asna.200410342
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.127-133
  • Çanakkale Onsekiz Mart University Affiliated: Yes


New BVR light curves and photometric analysis of the eclipsing binary star CN And are presented. The shape of the light curves are typical of beta Lyr type, and there are large asymmetries between maxima. The BVR light curves and the radial velocity curves (from Rucinski et al. 2000) were solved with the Wilson-Devinney method, simultaneously. The results suggest that CN And is a almost contact binary system, in which the component stars are filling similar to 99% of their Roche lobes. We discuss the model with a large dark starspot on the more massive star and a bright substellar spot on the companion to account for the light curve asymmetries. The absolute parameters of the system were also derived. The system resembles the near contact binary V1010 Oph according to its Roche configuration and light curve asymmetries. We, also, discuss the evolution of the system: it seems to be in a transition phase to the contact era. All previous times of minimum light were collected and combined with the new ones presented in this work. The variation of the orbital period of the system was then analyzed. The results reveal that the orbital period has a secular decrease of about 1.98 +/- 0.04 sec per century, which corresponds to a conservative mass transfer from the more to the less massive component at a rate of (1.52 +/- 0.09) x 10(-7)m(circle dot)/yr or a mass loss from the primary component due to magnetic stellar winds at a rate of (7.83 +/- 0.09) x 10(-8)m(circle dot)/yr.